Abrading machine for a preformed orthodontic band

ABSTRACT

A MACHINE FOR FORMING A ORTHODONTIC INCISOR, CUSPID, BICUSPID OR MOLAR BAND IS PROVIDED. THE MACHINE IS PROVIDED WITH OPPOSED PERIPHERAL ABRADING WHEELS WHICH ARE PENDANTLY SUPPORTED WITH DRIVE MOTORS ON THE LOWER ENDS OF THE PENDANT ARMS AND A CONVEYOR MEANS MOVES THE BANDS INTO GRINDING POSITION.

May 11, 1971 F, R, M|| ER ETAL 3,578,424

ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9, 1968 4Sheets-Sheet l J0 waan May 11, 1971 F. R. MILLER ETAL 3,578,424

` ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9. 1968 4Sheets-Sheet 2 ,....f Aw. 6. M ,Vf W \Ifu/na 4 new e F @M a@ MMM N. a .nw m ,ad WM v .Iv l u, r 4 dr a 1 MM Y wf M M ...xii 7 4.4 `Vf i May 11,1971 F. R. MILLER ETAI- ED ORTHODONTIC BAND 4 4 sheets-sheet s FiledAug. 9, 1968 fum May 11, 197l F. R. MILLER ETAL 3,578,424

ABRADING MACHINE FOR A PREFORMED ORTHODONTIC BAND Filed Aug. 9. 1958 4Sheets-Sheet;

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11 am y w y 220, i526. f@ Ms United States Patent Office 3,578,424Patented May 1l, 1971 3,578,424 ABRADIN G MACHINE FOR A PREFORMEDORTHODONTIC BAND Frank R. Miller, Bradbury, and Raymond E. Dillberg,

Temple City, Calif., assignors to Ormco Corporation,

Glendora, Calif.

Filed Aug. 9, 1968, Ser. No. 751,555 Int. Cl. B24b 5 00 U.S. Cl. 51-89 5Claims ABSTRACT OF THE DISCLOSURE A machine for forming an orthodonticincisor, cuspid, bicuspid or molar band is provided. The machine isprovided with opposed peripheral abrading wheels which are pendantlysupported with drive motors on the lower ends of the pendant arms and aconveyor means moves the bands into grinding position.

BACKGROUND OF THE INVENTION It is usual for the orthodontist to besupplied with a kit of tooth bands which are used in conjunction withother orthodontic devices and attachments. The tooth bands are fittedonto the teeth of the patient on a trial and error basis. The band mustbe ductile to permit it to be fitted exactly to the contours of theindividual tooth. For sullicient strength and yet sutcient ductility thewalls of the prior art bands have a thickness of the order, for example,of 3-6 mils.

The wall thickness of the prior art bands has created problems in theinterproximal area since substantial tooth separation is required whenthe prior art bands are fitted into the mouth of the patient. Thisfitting can be painful, and the large wall thickness also results in asubstantial space between the teeth to close after the bands have beenremoved. However, prior to the present invention, any attempt to providea thinner band, especially for the molars, has resulted in a concomitantloss in strength of the band, which could not be tolerated.

In the practice of the present invention, however, the interproximal ormesial and distal sides of the band are thinned by a mild abrading orbuing action. An appropriate metal such as stainless steel is used, sothat the resulting thinning f the band at these areas is accompanied bya simultaneous hardening of the metal in the band so that no loss instrength is encountered. Although there is a loss in ductility in thebuffed areas of the band, the remaining portions of the band which areunaffected by the bufling action provide the required ductility so as topermit the band to be fitted onto the tooth of the patient.

That is, the thinned walls of the band treated in accordance with theteaching of the present invention are strengthened by the abradingaction. This means that there is no overall loss in strength of theband, and the remaining portion of the band remains sufficiently ductileto allow the necessary forming of the band over the tooth, as the bandis fitted into the mouth of the patient. In the case of the molar bands,the upper or occlusal edge of the thinned parts is usually left in itsoriginal dimensions, so as to provide the orthodontist with a strongnon-cutting edge to permit him to push the band down over the toothwithout crumpling or bending of the edge.

Therefore, the hands formed by the machine of the present invention,having their interproximal portions thinned, are advantageous in thatthere is less total space between the teeth to close after the bandshave been removed. Moreover, the application of the bands is lesspainful since there is less initial separation of the teeth required.This latter factor often results in less work for the orthodontistsince, in many instances, the initial tooth separation step may beeliminated. Also, the use of the bands results in fewer problems oftooth relapse and rotation, as well as in greater patient comfort.

The improved buing or abrading machine to be described causesinterproximal portions of the wall of the band to be thinned, by holdingthe band between a pair of buing or grinding wheels, or theirequivalent, for a timed interval and determined pressure. The bufiingwheels are suspended as pendants and appropriate counterweights may beprovided so that the Wheels bear against the sides of the band beingtreated with just the required amount of force so as to achieve theobjective of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of atypical preformed molar band which may be formed by the machine of theinvention;

FIG. 2 is a top view of the preformed molar band of FIG. 1;

FIG. 3 is a side view, partly in section, showing the band of FIG. 1, astreated by the machine of the invention;

FIG. 4 is a front elevational view of an abrading machine for thinningthe sides of the band of FIGS. 1 3, and which is constructed inaccordance with the concepts of the invention;

FIG. 5 is a rear elevation of the machine of FIG. 4;

FIG. 6 is a fragmentary section showing a portion of one of the buffingwheels used in the machine of FIGS. 4 and 5, the other buing wheelhaving a similar construction;

FIG. 7 is a further front view of the machine of FIGS. 4 and 5,additionally showing a jig assembly in a withdrawn stand-by position;

FIG. 8 is a view like FIG. 7 of the machine and showing the jig assemblyin an upright operative position, whereby tooth bands may be broughtthereby between a pair of buing wheels in the practice of the invention;

FIG. 9 is a side view of the aforesaid jig assembly and showing itsvarious internal components;

FIG. 10 is an end view of the jig assembly of FIG. 9 taken essentiallyalong the line 10-10 of FIG. 9, and showing particularly a Genevacoupling which is used in the assembly;

FIG. 11 is a further end view of the jig assembly of FIG. 9 taken alongthe line 11-11 of FIG. 9, and showing particularly a cam operatedcontrol; and

FIG. 12 shows the details of a portion of the jig assembly whichsupports a tooth band, so as to convey the tooth band to the grindingwheels for buiiing purposes.

DETAILED DESCRIPTION OF THE INVENTION The tooth band shown in FIGS. l-3,as mentioned above, is a preformed molar band. The band is designated10, for example, and, as shown, includes a distal side, a mesial side, abuccal side and a lingual side. When iitted in the mouth of the patient,for example, the buccal side is to the outside and the lingual side isto the inside. The tooth band also includes an upper edge, designatedthe occlusal edge, and a lower edge designated the gingival edge. In thepractice of the present invention, and as best shown in FIG. 3, themesial and distal sides are thinned by an abrading or buing action. Inthe case of the molar bands, the occlusal and gingival edges arepreferably unthinned, so as to provide a surface for the orthodontist toforce the 'band down over the tooth, with suicient edge strength toresist bending.

As mentioned above, an appropriate metal is used to form the bands, sothat the bung and abrading action produces a simultaneous hardening ofthe metal in the band in the affected areas, so that there is no overallloss in strength. Moreover, the ductility of the remainder of the bandis suflicient, so that the bands may be fitted onto the tooth, as easilyas the prior art bands.l The resulting thinning in the interproximalcontact areas provides the feature outlined specifically above.

The grinding machine of the invention is shown specifically in FIGS.4-12. As shown in FIG. 4, for example, the machine includes a pair ofbuffing or abrading wheels 100 and 102, these wheels being rotatablymounted on the lower ends of a corresponding pair of arms 104 and 106.The arms, in turn, are pivotally mounted at their upper ends by shafts108 and 110. The shafts are rotatably mounted in pillow block bearings11211, 112b and 11411, 114b. The pillow blocks are mounted on ahorizontal shelf 116 which is supported by supports 118. The supports118, in turn, are mounted on an appropriate base 119. It will beappreciated, of course, that the wheels 100 and 102 may be replaced byother suitable abrading or buiiing means such as movable abrasive belts,or the like. Moreover, the abrading or buing means may be stationary andthe bands rotated or otherwise moved relative thereto.

The buiiing wheels 100 and 102 in the illustrated ernbodiment aresupported in a pendant manner on the arms 104 and 106, and are free toswing back and forth about the axes of rotation of the shafts 108 and110. Drive motors 120 and 122 for the buing Wheels are also mounted onthe lower ends of the pendant arms 104 and 106, behind the correspondingbufling wheels 100 and 102 in axial alignment, and with their driveshafts extending through the arms and mechanically coupled to therespective bufling or abrading wheels. The drive motors are connected toan appropriate electrical source through electrical leads 12011 and12211 and through a switch 123.

The bufiing or abrading wheels 100 and 102 may each include a rim ofhard rubber, plastic or felt as shown, for example, as 100a in FIG. 6.The rim may be impregnated with a grinding compound to enhance theactual abrading or buiiing action on the interproximal areas of eachtooth band, as the band is held between the two bufting wheels. Theforce with which the buing wheels engage the band being buffed may beestablished, for example, by an appropriate setting of counterweights122, 124 and 126, 128 on respective shafts 130, 132. The shafts 130 and132 extend out from the upper ends of the respective arms 104 and 106.

A pair of uid cylinders 137 and 139 of any appropriate type responds topressure in a line 136 (FIG. 5) to drive plungers against a pair of arms10411 and 104k which extend down from the motors 120 and 122. Thisaction serves to swing the two arms 104 and 106 in opposite directionsand thereby separate the buiiing wheels 100 and 102. This action occurs,for example, between bufiing or abrading operations and when no buffingor abrading action is desired on the member placed between the buffingwheels 100 and 102, as will be described.

A jig holding assembly 200 for conveying the bands to be treated to thebufiing or abrading wheels 100 and 102 is best shown in FIGS. 7 and 8.`Of course, other suitable types of conveyors may be used. The jigassembly is hinged to the base 119 so that it may be tilted back (FIG.7) to a standby position when not in use; or moved angularly to anupright position in which the tooth bands to be thinned by the buflingor abrading wheels 100 and 102 may be successively moved between thewheels by the jig assembly.

The jig assembly 200 rotatably supports a wheel 202, which is best seenin FIG. 11. The wheel 202 includes a series of radial members 204 whichextend beyond the peripheral edge of the wheel 202, and whoseextremities serve as support jigs for the bands to be thinned by thebuiiing or abrading Wheels 100, 102. That is, each member 204 includesat its extremity a finger 20411 which extends radially beyond theperiphery of the wheel. The

4 finger 20411 is positioned in facing relationship with another iinger204b. The latter finger is integral with the wheel itself and isstationary. The fingers 20411, 204b serve as supports for the tooth bandwhich is looped around the fingers.

Each member 20411 is pivotally mounted on a pin 205 in a bracket 203 onthe side of the wheel 202 for movement normal to the plane of the wheel.The member 204 is biased out from the plane of the wheel by a spring207, so that the fingers 20411, 204b are normally biased apart firmly tohold the band in its position around the fingers. The extent ofdisplacement between the fingers is limited by a screw 209. Now, whenthe wheel 202 turns to move the band on the fingers 20411, 204b betweenthe buffing wheels 100, 102, the interproximal sides of the band arebuffed or abraded and thinned to the desired shape and dimension, asdescribed in conjunction with FIGS. 1-3.

As the wheel 202 rotates, cam follower rollers 206 on the other end ofthe pivotally mounted members 204 engage a switch actuator 208 if thereis no band about the fingers 20411, 204b. If there is a band around thefingers, it holds the rollers up out of engagement with the switchactuator and against the spring bias of the springs 207. When a roller206 engages the switch actuator 208, a microswitch 230 is operated.

The operation of the microswitch 230 operates a solenoid valve 141 (FIG.5) in the fluid line 136. This causes the iiuid cylinders 137, 139 tooperate and spread the bufiing or abrading wheels 100, 102. Thisprotects the lingers 20411 and 204b from being ground down by thebufiing or abrading wheels when no band is supported thereby.

The wheel 202 is mounted in a bracket 220 on a shaft 222. The shaft 222is driven by an electric motor 224 which also is mounted on the bracket220 (FIG. 9). The motor drive shaft 225 is coupled to the shaft 222through a Geneva coupling or other such mechanism 226 (FIG. l0). Thisdrive causes the Wheel 202 to rotate in an intermittent manner so thateach tooth band supported on the fingers 20411, 204b at the end of itsmembers 204 may be held in a bufiing or abrading position between thebuffing or abrading wheels and 102 for a predetermined interval so thatthe desired bufiing or abrading action may proceed to predetermineddimensions.

The cam 208 is pivotally coupled to the microswitch 230 (FIG. 11). Awheel 232 is rotatably mounted on the cam 208 and is spring-biased by aspring 234 against a detent wheel 236. The detent wheel 236 is mountedon the shaft 222 to be driven by the motor 225 through the Genevacoupling or other mechanism 226. The detent wheel closes the microswitchwhile the tooth band held by the corresponding member 24 is movedbetween the bufiing or abrading wheels 100 and 102, so as to cause thebufling or abrading wheels to swing apart until the band is actually inposition and ready for thinning.

As the wheel 202 turns, a cam 250 engages the cam followers 206 to pivotthe members 204 about their pins 205 in FIG. 12 and close the fingers20411 and 204b towards one another so that a band can be placed over thefingers at the loading station (for example, to the left in FIG. 11).Then, as the wheel 202 turns, the cam follower 206 moves oi the end ofthe cam 250 and the fingers 20411 and 204b are spring-biased apart bythe spring 207 and against the inner edge of the tooth band placedthereon, firmly to hold the tooth band in place. As mentioned, if notooth band has been placed over the fingers, the corresponding camfollower 206 next engages the switch actuator 208 in FIG. 11 to actuatethe microswitch 230 and separate the bufiing or abrading wheels 100 and102. This occurs as the corresponding member 204 approaches the buflingor abrading Wheels, and for the interval the corresponding member hasits fingers 20411 and 204b in position between the wheels.

It will be appreciated, therefore, that the machine described aboveconstitutes a convenient instrumentality for thinning the interproxirnalarea of tooth bands, so that the tooth bands may exhibit the desiredcharacteristics as described above. As pointed out previously, althougha particular type of molar band is disclosed in FIGS. 1 3, the thinningprinciples of the present invention may be applied to any orthodontictooth band in which the problems enunciated above are encountered.

Therefore, while the invention has been described in one of its aspects,other equivalent aspects may be practiced without departing from thespirit thereof. The following claims are intended to cover the variousaspects of the invention.

What is claimed is:

1. A machine for bufiing or abrading selected portions of a thin-walledductile orthodontic tooth band, said machine including:

-bracket support means;

first and second arms pivotally mounted at their upper ends to saidbracket support means and extending vertically downwardly therefrom inside-by-side relationship;

grinding means comprising first and second bufling or abrading wheelsrotatably mounted in side-by-side bufng or abrading relationship on thelower ends of said arms to be pendantly supported thereby from saidbracket means to be free to swing back and forth about the respectivepivotal axes of said arms and to engage such a tooth band with just therequired amount of force to provide a bufiing or abrading action withoutcrushing the band;

first and second drive motors for said bufling or abrading wheelsrespectively mounted on the lower ends of said arms and respectivelymechanically coupled to said buing or abrading wheels; and

a conveyor assembly for moving successive thin-walled ductileorthodontic tooth bands to said grinding means to be buifed therebywithout crushing.

2. The machine defined in claim 1 and which includes adjustablecounterweights coupled to said arms to establish the force with whichsaid first and second butfng or abrading wheels engage the aforesaidbands.

3. The machine defined in claim 1, in which said conveyor assemblyincludes a wheel having radially extending members providing supportjigs for said bands, said support jigs being brought successivelybetween said first and second buing or abrading wheels as said jigassembly rotates, an electric drive motor, and a coupling meansintercoupling said drive motor and said conveyor assembly wheel toimpart intermittent rotational movement to said conveyor assembly wheel.

4. The machine defined in claim 3 in which the extremities of saidradially extending members extend beyond the periphery of said conveyorassembly wheel, and each includes a pair of fingers around which one ofsaid bands may be positioned, and which separate from one another uponradial movement of the corresponding radially extending members to holdthe band securely in place.

5. A machine for bufling or abrading selected portions of an orthodonticband, said machine including:

bracket support means; first and second arms pivotally mounted at theirupper ends to said bracket support means and extending verticallydownwardly therefrom in side-by-side relationship; first and secondbuting or abrading wheels rotatably mounted in side-by-side buing orabrading relationship on the lower ends of said arms t0 be pendantlysupported thereby from said bracket support means; and a conveyorassembly for moving successive bands to said buing or abrading wheels tobe butfed thereby, said conveyor assembly including a wheel havingradially extending members providing support jigs for said bands, saidsupport jigs being brought successively between said first and secondbuing or abrading wheels as said jig assembly rotates, the extrcmitiesof said radially extending members extending beyond the periphery ofsaid conveyor assembly wheel, and each including a pair of fingersaround which one of said bands may be positioned, and which separatefrom one another upon radial movement of the corresponding radiallyextending members to hold the band securely in place, and which includescam followers on said members, and control means coupled to said arms tocause said buiiing or abrading wheels to swing away from one another,said control means having a switch actuator engaged by said camfollowers in the absence of a band around the aforesaid fingers of saidmembers to produce an actuation on said control means.

References Cited UNITED STATES PATENTS 2,691,254 10/1954 Robbins 5l-891,926,577 9/1933 Behle 5l-89 l,205,696 ll/l9l6 Beck 51-89 2,242,801 5/1941 Richardson 51-237X 3,430,388 3/1969 Gabrielli 51-l34 FOREIGNPATENTS 14,579 ll/1887 'Great Britain 51-89 322,913 10/1924 GreatBritain 5l-89 HAROLD D. WHITEHEAD, Primary Examiner

